The changing spectrum of fungal keratitis in south Florida

Microbiological Profile of Culture-Positive Fungal Keratitis

PURPOSE

To examine the microbiological profile of cases of culture-positive fungal keratitis presenting to a tertiary eye care center in eastern India.

METHODS

Microbiology records of all culture-positive microbial keratitis patients presenting to L V Prasad Eye Institute, Bhubaneswar, between January 2020 and December 2021, were retrospectively reviewed. Collected data included smear results of culture-positive fungal or mixed infections, the species isolated, and the time taken for organisms to grow in each media.

RESULTS

Fungal keratitis formed 36% of all culture-positive microbial keratitis, whereas mixed infections (fungi and other organisms) formed 8.5%. The most common fungal species isolated was Fusarium spp. (25.8%). The most common bacteria involved in mixed infection with fungi was Staphylococcus spp. (54.8%). The positivity of potassium hydroxide+calcofluor white stain in detecting fungal filaments was 89.0% and that of Gram stain was 76.1%. Culture-positive cases of fungal keratitis showed most frequent growth on potato-dextrose agar (77.6%). A similar pattern was observed in culture-positive mixed infections (Sabouraud dextrose agar [SDA]: 84%). Most frequent growth of bacteria in mixed infections was seen in thioglycolate broth (54.7%). The shortest time to achieve significant fungal growth was observed in blood agar (BA) and chocolate agar (CA) (2.2/2.3 days, and 1.8/2 days for fungal keratitis and mixed infections, respectively). Filamentous hyaline fungi took the shortest time to achieve significant growth (2.8 days), whereas yeast forms took the longest (5 days).

CONCLUSION

This study highlights the importance of combined use of both solid and liquid culture media, especially potato dextrose agar (PDA)/SDA and CA, to arrive at a definitive diagnosis of fungal keratitis and possible bacterial co-infection, which forms a significant proportion of cases with fungal keratitis. In resource-poor laboratories, two culture media, either SDA or PDA, along with BA, may be plated to detect mixed infections. Examination of stained smears of corneal samples provides an inexpensive method of rapid diagnosis of fungal keratitis when culture media is not available.

Locality is the strongest predictor of expert performance in image-based differentiation of bacterial and fungal corneal ulcers from India

PURPOSE

This study sought to identify the sources of differential performance and misclassification error among local (Indian) and external (non-Indian) corneal specialists in identifying bacterial and fungal keratitis based on corneal photography.

METHODS

This study is a secondary analysis of survey data assessing the ability of corneal specialists to identify acute bacterial versus fungal keratitis by using corneal photography. One-hundred images of 100 eyes from 100 patients with acute bacterial or fungal keratitis in South India were previously presented to an international cohort of cornea specialists for interpretation over the span of April to July 2021. Each expert provided a predicted probability that the ulcer was either bacterial or fungal. Using these data, we performed multivariable linear regression to identify factors predictive of expert performance, accounting for primary practice location and surrogate measures to infer local fungal ulcer prevalence, including locality, latitude, and dew point. In addition, Brier score decomposition was used to determine experts' reliability ("calibration") and resolution ("boldness") and were compared between local (Indian) and external (non-Indian) experts.

RESULTS

Sixty-six experts from 16 countries participated. Indian practice location was the only independently significant predictor of performance in multivariable linear regression. Resolution among Indian experts was significantly better (0.08) than among non-Indian experts (0.01; P < 0.001), indicating greater confidence in their predictions. There was no significant difference in reliability between the two groups ( P = 0.40).

CONCLUSION

Local cornea experts outperformed their international counterparts independent of regional variability in tropical risk factors for fungal keratitis. This may be explained by regional characteristics of infectious ulcers with which local corneal specialists are familiar.

Amniotic membrane transplantation combined with conjunctival flap covering surgery for the treatment of corneal perforations in fungal keratitis

Purpose

To investigate the efficiency of amniotic membrane transplantation (AMT) combined with conjunctival flap covering surgery (CFCS) for patients with corneal perforations in fungal keratitis (FK).

Methods

In this non-comparative, retrospective case series, 16 participants of corneal perforation in FK were successfully treated by a combination of multilayer AMT and bipedicle conjunctival flap with partial tenon's capsule. Corneal healing, recurrence of FK, visual acuity, and relevant complications were reported as outcome measures.

Results

Sixteen patients (13 male, 3 female) had a mean age of 58.8 ± 10.3 (range 29-72) years. The mean diameter of corneal perforation was 1.9 ± 0.7 (range 0.5-2.8) mm. Corneal perforations healed and all the patients preserved their eyeballs. During the 11.0 ± 4.4 (range 6-18) months of follow-up, there was no recurrence of FK in any of these cases. Visual acuity improved in 15 eyes (93.8 %) and remained unchanged in 1 patient (6.3 %) who had no light perception when first admitted. All 6 patients who accepted secondary keratoplasty showed improved best corrected visual acuity of more than 4 lines. The most frequently found fungi were Aspergillus species (6 of 16, 37.5 %) and Fusarium species (4 of 16, 25.0 %), followed by 1 Scedosporium apiospermum (1 of 16, 6.3 %).

Conclusions

Combination AMT with CFCS is a safe and effective surgery for patients with corneal perforations in FK, particularly where eye banks and fresh corneas are not available. This surgery could preserve the integrity of the eyeball and avoid the recurrence of FK. Besides, it provides a greater opportunity for further optical keratoplasty.

Microbial Keratitis Isolates at a Midwestern Tertiary Eye Care Center

PURPOSE

The aim of the study was to describe the pathogen, antimicrobial susceptibility, and trends over time of microbial keratitis (MK) at a Midwestern tertiary eye center.

METHODS

Patients with MK were identified in the electronic health record from August 2012 to December 2021. Diagnostic laboratory tests with an MK diagnosis were identified and classified as laboratory positive or laboratory negative. Laboratory-positive infections were categorized as bacterial (gram-positive, gram-negative, or acid-fast bacilli), fungal, viral, Acanthamoeba , or polymicrobial. Antimicrobial susceptibilities were obtained. Trends over time were assessed using linear regression.

RESULTS

Of 3288 patients with MK identified, 1012 (30.8%) had laboratory tests performed. Laboratory-positive infections (n = 499, 49.3%) were bacterial in 73.5% (n = 367) of cases, fungal in 7.8% (n = 39), viral in 1.6% (n = 8), Acanthamoeba in 1.4% (n = 7), and polymicrobial in 15.6% (n = 78). Of bacterial infections, 70% (n = 257) were gram-positive, with coagulase-negative Staphylococcus (CoNS; 31%) and Staphylococcus aureus ( S. aureus ; 23%) as the most common pathogens. Bacteria were acid-fast bacilli in 1.9% (n = 7) of cases and gram-negative in 28.1% (n = 103), with Pseudomonas aeruginosa as the predominant pathogen (47.7%). S. aureus showed antibiotic resistance from 0% (vancomycin and gentamicin) to 50% (erythromycin); CoNS from 0% (vancomycin, gentamicin, and moxifloxacin) to 64% (erythromycin). The rate of laboratory-negative MK significantly increased over time (slope estimate = 2.1% per year, P = 0.034). Rates of bacterial, fungal, viral, Acanthamoeba , and polymicrobial infections were stable over time (all slope P > 0.05).

CONCLUSIONS

Bacterial keratitis accounted for most MK cases. Gram-positive bacteria were the most common isolates. CoNS and S. aureus were universally susceptible to vancomycin. Rates of MK infection types were stable over time.

Lasiodiplodia theobromae keratitis: A rare tropical fungal keratitis in a non-tropical climate

Purpose

We present the clinical and histopathological findings of a geographically unique Lasiodiplodia theobromae fungal keratitis case in North Carolina. L. theobromae is a rare cause of fungal keratitis, and all but one of the 51 previously reported cases have occurred in patients living in the tropics.

Observations

A man in his early 50s developed L. theobromae keratitis after being struck in the left eye by a piece of debris while using a flexible-cord weed trimmer. Intracapsular lensectomy and penetrating keratoplasty were necessary when initial antimicrobial therapy was ineffective. The best-corrected visual acuity was 20/40 four years postoperatively.

Conclusions and Importance

Our patient is only the second example of L. theobromae keratitis in a patient living in a sub-tropical climate and the first case in the U.S.A. outside of Florida. Additional in-vitro antibiotic sensitivity testing and documentation of more clinical cases are needed to define the optimal therapy for Lasiodiplodia theobromae keratitis.

Corneal Culture and Antibiotic Susceptibility Results for Microbial Keratitis in the Mid-Atlantic Region of the United States, 2016 to 2020

OBJECTIVE

To examine the microbial distribution and antimicrobial susceptibility of culture-positive microbial keratitis at a large tertiary referral center in the mid-Atlantic region of the United States.

METHODS

Retrospective review of culture-positive microbial keratitis cases at the Wilmer Eye Institute from 2016 through 2020.

RESULTS

Of the 474 culture-positive microbial keratitis cases, most were bacterial (N=450, 94.9%), followed by fungal (N=48, 10.1%) and Acanthamoeba keratitis (N=15, 3.1%). Of the 450 bacterial isolates, 284 (69.5%) were gram-positive organisms, whereas 157 (28.4%) were gram-negative organisms. The most common bacterial species isolated was coagulase-negative Staphylococcus spp (N=154, 24.8%), and the most common gram-negative isolate was Pseudomonas aeruginosa (N=76, 12.3%). Among fungi, the most common isolates were Candida (N=25, 45.4%), whereas Fusarium (N=6, 10.9%) and Aspergillus (N=3, 5.5%) were less common. Of the 217 bacterial isolates tested for erythromycin susceptibility, 121 (55.7%; ∼60% of coagulase-negative staphylococci and corynebacteria tested) showed resistance to erythromycin.

CONCLUSIONS

Microbial keratitis in the Baltimore Mid-Atlantic region of the United States is most commonly caused by bacteria, with fungi and acanthamoeba being less common. Gram-positive bacterial infections predominate. Among fungal keratitis cases, Candida species are more commonly encountered than are filamentous species. Use of erythromycin as infection prophylaxis should be reexamined. Findings from our study may guide empiric treatment in this geographic region.

Mycoviruses in Fungi: Carcinogenesis of Fungal Agents May Not Always Be Mycotoxin Related

Certain viruses have been found to induce diverse biological pathways to carcinogenesis, evidenced by the presence of viral gene products in some tumors. Despite the fact that many fungal agents contain mycoviruses, until recently, their possible direct effects on human health, including carcinogenesis and leukemogenesis, had not been explored. In this regard, most studies of fungal agents have rightly concentrated on their mycotoxin formation and effects. Recently, the direct role of yeasts and fungi in the etiology of cancers, including leukemia, have been investigated. While greater attention has been placed on the carcinogenic effects of Candida, the role of filamentous fungi in carcinogenesis has also been explored. Recent findings from studies using the enzyme-linked immunosorbent assay (ELISA) technique indicate that the plasma of patients with acute lymphoblastic leukemia (ALL) uniformly contains antibodies for a certain mycovirus-containing Aspergillus flavus, while controls are negative. The exposure of mononuclear leukocytes from patients with ALL in full remission, and long-term survivors, to the product of this organism was reported to result in the re-development of typical genetics and cell surface phenotypes characteristic of active ALL. Mycoviruses are known to be able to significantly alter the biological characteristics and functions of their host. The possible carcinogenic and leukemogenic role of mycoviruses, with and without their host, needs to be further investigated.

Glabridin Inhibits Aspergillus fumigatus Growth and Alleviate Inflammation Mediated by Dectin-2 and NLRP3 Inflammasome

PURPOSE

The research was used to uncover the mechanism of glabridin in Aspergillus fumigatus keratitis in anti-fungus and anti-inflammation.

METHODS

In vitro, RAW 264.7 cells were infected with A. fumigatus with incubation of glabridin in different concentrations. Real-time quantitative polymerase chain reaction (RT‑qPCR), Western blot, and enzyme-linked immunosorbent assay (ELISA) were used to assess the inflammatory severe and alternation with the intervention of Dectin-2 siRNA and glabridin. In vivo, A. fumigatus keratitis mouse models were established by spore intra-stromal injection and treated with glabridin or PBS. And disease scores, inflammatory mediators, and periodic acid-schiff (PAS) staining were exhibited to demonstrate the therapeutic efficiency of glabridin in vivo. Morphological interference assay monitored fungal germination. Scanning and transmission electron microscopy were used to observe the growth of fungi.

RESULTS

In RAW 264.7 cells and mouse keratitis models, noncytotoxic 16 μg/mL glabridin showed significant inhibition in the expression of Dectin-2, NLRP3, Caspase-1, IL-1β, and TNF-α after A. fumigatus infection, almost similar to the intervention of Dectin-2 siRNA. PAS staining illustrated the reduced hyphal distribution in cornea stroma with glabridin treatment. Glabridin remarkably inhibited A. fumigatus growth through delaying germination and disrupting the integrity of the hyphae membrane.

CONCLUSION

Glabridin plays an anti-inflammatory role in A. fumigatus challenge via suppression of the Dectin-2 and NLRP3 inflammasome, and plays an anti-fungal role through delaying germination and changing the hyphal integrity.KEY MESSAGESGlabridin plays an anti-inflammatory role in A. fumigatus infection of RAW264.7 cells in a concentration-dependent manner and through Dectin-2 mediation.Glabridin decreases fungal distribution and inflammation in mouse A. fumigatus keratitis.Glabridin inhibits A. fumigatus growth by delaying germination and disrupting cellular structure in vitro.

Characteristics of In Vitro Culture and In Vivo Confocal Microscopy in Patients with Fungal Keratitis in a Tertiary Referral Hospital in Central China

PURPOSE

To investigate the characteristics of in vitro culture and in vivo confocal microscopy (IVCM) in patients with fungal keratitis (FK) presented in a tertiary referral hospital in central China.

METHODS

In this noncomparative retrospective study, patients with the diagnosis of FK between October 2021 and November 2022 were reviewed. An IVCM and fungal culture (corneal scraping specimens) were performed, and the characteristics were analyzed.

RESULTS

During October 2021 and November 2022, 85 patients were diagnosed with FK. From 63 culture-positive cases, 8 species of fungus were identified. The proportions of isolated fungal species were Fusarium and Aspergillus equally accounting for 33.3% (21 of 63), Alternaria 9.5% (6 of 63), Curvularia 6.3% (4 of 63), Scedosporium apiospermum 6.3% (4 of 63), Paecilomyces lilacinus 3.2% (2 of 63), Exserohilum 3.2% (2 of 63), and Candida 4.8% (3 of 63), respectively. In positive culture cases, IVCM was found to be positive for hyphae or spores in 61 of 63 patients (96.8%). Different fungal species had a variety of cultural characteristics and IVCM manifestations.

CONCLUSIONS

In a tertiary referral hospital in central China, Fusarium species, Aspergillus species, and Alternaria species were the 3 most common isolated fungal pathogens, and the proportion of Aspergillus species was significantly higher than that in other regions of China. Careful lesion depth examination by IVCM and OCT should be taken before lamellar keratoplasty to avoid postoperative recurrence. Identifying the IVCM image and culture characteristics will facilitate rapid diagnosis and proper treatment, but IVCM cannot yet replace fungal cultures to distinguish between different fungal species.

Fungal keratitis in Iran: Risk factors, clinical features, and mycological profile

Introduction

This study was intended to investigate the clinical features and predisposing factors of fungal keratitis (FK), as well as molecular identification and antifungal susceptibility of causative agents in Tehran, Iran.

Methods

This cross-sectional study was carried out from April 2019 to May 2021. All fungi isolates were identified using conventional methods and were confirmed by DNA-PCR-based molecular assays. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) was used to identify yeast species. Minimum inhibitory concentrations (MIC) of eight antifungal agents were assessed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) microbroth dilution reference method.

Results

Fungal etiology was confirmed in 86 (7.23%) of 1189 corneal ulcers. A significant predisposing factor for FK was ocular trauma caused by plant materials. Therapeutic penetrating keratoplasty (PKP) was required in 60.4% of cases. The predominant fungal species isolated was Fusarium spp. (39.5%) followed by Aspergillus spp. (32.5%) and Candida spp. (16.2%).

Discussion

The MIC results indicate that amphotericin B may be appropriate for treating FK caused by Fusarium species. FK caused by Candida spp. can be treated with flucytosine, voriconazole, posaconazole, miconazole, and caspofungin. In developing countries such as Iran, corneal infection due to filamentous fungi is a common cause of corneal damage. In this region, fungal keratitis is observed primarily within the context of agricultural activity and subsequent ocular trauma. Fungal keratitis can be managed better with understanding the "local" etiologies and antifungal susceptibility patterns.

Ophthalmic Trauma Malpractice in the Ophthalmic Mutual Insurance Company Database

PURPOSE

To review ophthalmic trauma malpractice claims in the Ophthalmic Mutual Insurance Company (OMIC) database to determine the frequency and causes of litigation.

METHODS

A retrospective case series analysis of ophthalmic trauma claims from 2009 to 2019 was completed. Cases were selected only if the injury was secondary to trauma (e.g., fall, gunshot wound, paintball injury, etc.); iatrogenic traumatic surgical injuries were excluded.

RESULTS

31 closed cases associated with 40 total claims related to ophthalmic trauma out of 2565 claims (1.56%) in the OMIC database were analysed. 13 of the 31 cases (41.9%) were decided for the plaintiff. In decisions for the plaintiff, the median settlement amount was $330,000 (range $125,000-$1,000,000). The most frequent initial diagnoses were corneal abrasion (n = 10), hyphema (n = 5) and open-globe injury (n = 5), and the most common final diagnoses were endophthalmitis (n = 8), intraocular foreign body (n = 7) and retinal detachment (n = 7). The most common causes of malpractice litigation were a delay in referral or follow-up (n = 11) and failure to get appropriate imaging (n = 8). In the 13 cases decided for the plaintiff, experts concluded nine did not meet standard of care.

CONCLUSIONS

Ophthalmic trauma malpractice claims are very uncommon in the United States, however, the payout is higher than non-trauma settlements, and approximately 40% of cases were decided for the plaintiff. Care could be improved with a careful history and complete ophthalmic examination (with dilated fundoscopy), imaging in appropriate patients, meticulous documentation, and early sub-specialist referral when the diagnosis or management plan was unclear.

A 5-Year Retrospective Analysis of the Risk Factors, Treatment, and Prognosis of Patients With Fungal Keratitis in Heilongjiang, China

PURPOSE

To report the epidemiologic features, laboratory findings, and treatment outcomes of patients with fungal keratitis (FK) during a busy farming period (May, June, and September to November) in Heilongjiang Province, China.

DESIGN

Retrospective, observational case series.

METHODS

In total, 251 patients diagnosed with FK at the Eye Hospital, First Affiliated Hospital of Harbin Medical University, from 2017 to 2021 were identified. Medical records were retrospectively analyzed, and demographic features, risk factors, monthly distributions, clinical characteristics, laboratory findings, treatment strategies, and prognostic data were collected.

RESULTS

The number of FK cases in the busy farming period accounted for 74.1% (186/251) of the total. The mean patient age was 58.2±9.5 years. Males (66.7%) were more likely to develop FK than females (33.3%), and plant-related trauma was the main cause in 80.1% (149/186) of the cases. The most common causative fungal species was Fusarium (34.9%). In vivo confocal microscopy had the highest positivity rate for FK diagnosis (94.6%). The depth of hypopyon, depth of hyphae or spores, and infiltrate width were significantly positively correlated with delayed presentation.

CONCLUSIONS

Patients with a longer time of presentation to the hospital were more likely to undergo surgery because of topical medical therapy failure. The most important measures for FK prevention are the use of eye protection during outdoor work and visiting the hospital for treatment as soon as possible after eye injury.

Clinical Comparison of Fusarium Keratitis according to the Initial Potassium Hydroxide (KOH) Smear: A Retrospective Study in South Korea

Purpose. This study aimed to compare predisposing factors, clinical characteristics, treatment, and prognosis of Fusarium keratitis according to the result of the initial potassium hydroxide (KOH) smear. Methods. This is a retrospective study of cases with Fusarium keratitis between January 2000 and December 2019 at two tertiary hospitals in South Korea. Patients were divided into two groups depending on the KOH smear result (KOH-positive and KOH-negative group), and its clinical factors were analyzed. Results. Among 319 fungal keratitis, seventy-nine cases were identified with Fusarium keratitis. Forty-seven cases (59.5%) were negative in the initial KOH smear prior to their diagnosis. The most common predisposing factor for Fusarium keratitis was ocular trauma (55.7%). There were no significant differences in sex, occupation, ulcer size or shape, hypopyon, and initial visual acuity between the two groups. Differences were observed between the KOH-positive group and the KOH-negative group in terms of deep corneal infiltration (50.0% vs. 78.7%, $p=0.008$ ) and evisceration treatment (3.1% vs. 25.5%, $p=0.008$ ). The delayed time to initiate antifungal eye drops was longer in the KOH-negative group (1.13 ± 0.49 vs. 3.93 ± 4.89, $p=0.002$ ). Only the KOH-negative group combined bacterial infection. The significant risk factors for poor clinical outcomes were the central corneal lesion (odds ratio (OR) 3.50, $p=0.047$ ), a large ulcer size (size ≥ 7.5 mm2) (OR 4.98, $p=0.009$ ), and endothelial plaque (OR 7.00, $p=0.031$ ). Conclusion. Initial KOH-negative patients often needed evisceration and had worse final visual outcomes. The delay of prompt initiation of antifungal treatment and combined bacterial infection result in a poor prognosis. This study highlights the initial KOH effect on early diagnosis and early treatment of Fusarium keratitis.

Filamentous Fungal Keratitis in Greece: A 16-Year Nationwide Multicenter Survey

In a multicenter, prospective study of filamentous fungal keratitis in Greece, predisposing factors, etiology, treatment practices, and outcome, were determined. Corneal scrapings were collected from patients with clinical suspicion of fungal keratitis, and demographic and clinical data were recorded. Fungal identification was based on morphology, molecular methods, and matrix assisted laser desorption ionization time-of-flight mass-spectrometry. A total of 35 cases were identified in a 16-year study period. Female to male ratio was 1:1.7 and median age 48 years. Corneal injury by plant material, and soft contact lens use were the main risk factors (42.8% and 31.4%, respectively). Trauma was the leading risk factor for men (68.1%), contact lens use (61.5%) for women. Fusarium species were isolated more frequently (n = 21, 61.8%). F. solani was mostly associated with trauma, F. verticillioides and F. proliferatum with soft contact lens use. Other fungi were: Purpureocillium lilacinum (14.7%), Alternaria (11.8%), Aspergillus (8.8%), and Phoma foliaceiphila, Beauveria bassiana and Curvularia spicifera, one case each. Amphotericin B and voriconazole MIC₅₀s against Fusarium were 2 mg/L and 4 mg/L respectively. Antifungal therapy consisted mainly of voriconazole locally or both locally and systemically, alone or in combination with liposomal AmB. Cure/improvement rate with antifungal therapy alone was 52%, keratoplasty was required in 40% of cases, and enucleation in 8%. In conclusion, filamentous fungal keratitis in Greece is rare, but with considerable morbidity. A large proportion of cases resulted in keratoplasty despite appropriate antifungal treatment.Kindly confirm the given name and family name are correctly identified for all authros.ConfirmedJournal instruction requires a city and country for affiliations; however, these are missing in affiliations 1, 3, 4, 5, 6, 13. Please verify if the provided city and country are correct and amend if necessary.All provided cities and countries are correct.

The emerging threat antifungal-resistant Candida tropicalis in humans, animals, and environment

Antifungal resistance in humans, animals, and the environment is an emerging problem. Among the different fungal species that can develop resistance, Candida tropicalis is ubiquitous and causes infections in animals and humans. In Asia and some Latin American countries, C. tropicalis is among the most common species related to candidemia, and mortality rates are usually above 40%. Fluconazole resistance is especially reported in Asian countries and clonal spread in humans and the environment has been investigated in some studies. In Brazil, high rates of azole resistance have been found in animals and the environment. Multidrug resistance is still rare, but recent reports of clinical multidrug-resistant isolates are worrisome. The molecular apparatus of antifungal resistance has been majorly investigated in clinical C. tropicalis isolates, revealing that this species can develop resistance through the conjunction of different adaptative mechanisms. In this review article, we summarize the main findings regarding antifungal resistance and Candida tropicalis through an "One Health" approach.

Trends in the Microbiological Spectrum of Nonviral Keratitis at a Single Tertiary Care Ophthalmic Hospital in India: A Review of 30 years

PURPOSE

The aims of this study were to assess the trends in microorganisms from patients with infectious keratitis and to assess their antibiogram patterns at a tertiary eye care center in India.

METHODS

In this retrospective observational case series, microbiological records of all corneal ulcers were reviewed from 1991 to 2020 and assessed for trends in keratitis and antibiotic susceptibility using the χ2 test.

RESULTS

Of the total of 51,747 patients, 51.13% were culture positive. A decrease in bacteria was noted from 56% to 38%, with a parallel increase in fungal isolates from 24% to 51%. Gram-positive bacteria accounted for 70.8% of the total bacteria, a trend in rise of Streptococcus pneumoniae (31%) and a decreasing trend in prevalence of Staphylococcus epidermidis was observed over 30 years. Pseudomonas aeruginosa (55.5%) was the most prevalent gram-negative pathogen, whereas Fusarium spp. (33.1%) and Aspergillus spp. (32.4%) were the most common fungal isolates. The susceptibility of gram-positive organisms to cefazolin decreased from 95.5% to 66% (P = 0.0001), amikacin from 88% to 55% (P= 0.0001), and vancomycin from 98.9% to 90.7% (P < 0.05). A similar decrease in susceptibility was also significant for gram-negative organisms with piperacillin/tazobactam and chloramphenicol (P < 0.05). A significant trend toward increasing resistance against fluoroquinolones was also observed for ciprofloxacin (gram-positive organisms: 16% to 50%; gram-negative organisms: 11.5% to 18.7%), gatifloxacin (38% to 47%), and moxifloxacin (9.4% to 29%).

CONCLUSIONS

The spectrum of keratitis has changed, and fungus is now the predominant etiology. An increasing trend in resistance to all antibiotics studied would affect the empiric treatment, also suggesting regular surveillance.

Role of corneal biopsy in the management of infectious keratitis

PURPOSE OF REVIEW

The aim of this study was to review the existing literature and investigate the role of microbiologic culture and histopathologic examination of corneal biopsies in the management of infectious keratitis.

RECENT FINDINGS

Corneal biopsy continues to be a significantly useful tool in the diagnosis and tailored management of infectious keratitis. Several techniques can be employed for tissue collection, handling and processing to optimize diagnostic yield and maximize safety, including emerging femtosecond laser-assisted biopsy.

SUMMARY

Corneal opacities represent a significant cause of global blindness, and infectious keratitis is the most common cause. Organism identification in progressive infectious keratitis is essential for proper management. However, microbiological culture alone has a high rate of false-negative results. Records from the Bascom Palmer Eye Institute were retrospectively searched for patients between 1 January 2015, and 31 December 2019, who underwent corneal biopsy, therapeutic keratoplasty or endothelial graft removal for infectious keratitis and had specimens bisected and submitted for evaluation with both microbiologic culture and histopathologic examination. Detection of bacteria, fungus and mycobacteria was not statistically different between culture and histopathology. Microbiology and histopathology are complementary methods for the identification of causative microorganisms in corneal specimens with presumed infectious keratitis.

Mycobiomes of the Ocular Surface in Bacterial Keratitis Patients

Inflammation of the cornea is known as keratitis, and bacteria, fungi, protozoans, and viruses are the etiological agents of this disease. Delayed treatment of keratitis could result in loss of vision and, under certain severity conditions, the removal of an eye and its associated structures. In the current study, the ocular surface (conjunctiva and cornea) mycobiomes of individuals with bacterial keratitis were compared with the ocular mycobiome (conjunctiva) of healthy individuals, free of any ocular morbidity. Mycobiomes were generated through NGS approach using conjunctival swabs and corneal scrapings as the source of DNA from which ITS2 was amplified and sequenced, as a proxy to identify fungi. The results indicated significant changes in the alpha-diversity indices and in the abundance at the phylum and genera level. Hierarchical clustering using a heatmap showed that the mycobiomes were different. Furthermore, NMDS plots also differentiated the mycobiomes in the three cohorts, implying dysbiosis in the mycobiomes of the conjunctivae and corneal scrapings of bacterial keratitis individuals compared to control individuals. A preponderance of negative interactions in the hub genera in the conjunctival swabs of bacterial keratitis individuals compared to healthy controls further re-emphasized the differences in the mycobiomes. The dysbiotic changes at the genera level in conjunctivae and corneal scrapings of bacterial keratitis individuals are discussed with respect to their possible role in causing or exacerbating ocular surface inflammation. These results demonstrate dysbiosis in the ocular mycobiome in bacterial keratitis patients compared to healthy controls for the first time.

Microbial Keratitis in Nepal: Predicting the Microbial Aetiology from Clinical Features

Fungal corneal infection (keratitis) is a common clinical problem in South Asia. However, it is often challenging to distinguish this from other aetiologies, such as bacteria or acanthamoeba. In this prospective study, we investigated clinical and epidemiological features that can predict the microbial aetiology of microbial keratitis in Nepal. We recruited patients presenting with keratitis to a tertiary eye hospital in lowland eastern Nepal between June 2019 and November 2020. A structured assessment, including demographics, history, and clinical signs, was carried out. The aetiology was investigated with in vivo confocal microscopy and corneal scrape for microscopy and culture. A predictor score was developed using odds ratios calculated to predict aetiology from features. A fungal cause was identified in 482/642 (75.1%) of cases, which increased to 532/642 (82.9%) when including mixed infections. Unusually, dematiaceous fungi accounted for half of the culture-positive cases (50.6%). Serrated infiltrate margins, patent nasolacrimal duct, raised corneal slough, and organic trauma were independently associated with fungal keratitis (p < 0.01). These four features were combined in a predictor score. The probability of fungal keratitis was 30.1% if one feature was present, increasing to 96.3% if all four were present. Whilst microbiological diagnosis is the "gold standard" to determine the aetiology of an infection, certain clinical signs can help direct the clinician to find a presumptive infectious cause, allowing appropriate treatment to be started without delay. Additionally, this study identified dematiaceous fungi, specifically Curvularia spp., as the main causative agent for fungal keratitis in this region. This novel finding warrants further research to understand potential implications and any trends over time.

Gellan gum-based in situ gelling ophthalmic nanosuspension of Posaconazole

The formulation and delivery of highly hydrophobic drugs in an optimized dosage form is challenging to formulation scientists. Posaconazole has shown promising action in case studies against fungal keratitis. Biological macromolecules like gellan gum would aid in enhancing the availability of such drugs by increasing the contact time of the formulation. Herein, we propose a transmucosal ocular delivery system of Posaconazole by developing a gellan gum-based in situ gelling nanosuspension. The HPLC method for Posaconazole was developed and validated as per ICH guidelines. The nanosuspension was prepared by microfluidization and optimized by Quality by Design. The gellan gum concentration selected was 0.4% w/v based on the viscosity and mucoadhesion measurements. A greater zone of inhibition of ~ 15 mm was observed for the prepared nanosuspension as compared to ~ 11 mm for the marketed itraconazole nanosuspension. A potential irritancy score of 0.85, considered to be non-irritant, was observed for the developed nanosuspension. Higher drug release of ~ 35% was noted for the nanosuspension compared to about ~ 10% for the coarse suspension. Ex vivo corneal retention studies on excised goat cornea demonstrated ~ 70% drug retention in the tissue. Graphical abstract depicting the central hypothesis of the work.

Fungal Keratitis: Diagnostic Characteristics of the Potassium Hydroxide Preparation With Calcofluor White in Northern California

PURPOSE

The incidence of fungal keratitis demonstrates significant geographic and climatic variation. We report on the characteristics of the potassium hydroxide/calcofluor white (KOH-CFW) preparation observed at a tertiary center in Northern California, a region with a low incidence of fungal keratitis.

METHODS

Culture-proven cases of microbial keratitis during a 5-year period were retrospectively reviewed. The sensitivity, specificity, and posttest probabilities were determined for the KOH-CFW assay. These results were compared with documented clinical impression and values reported in the literature.

RESULTS

Three hundred three of 368 episodes of microbial keratitis during the study period documented the results of a fungal culture, KOH-CFW assay, and a clinical impression. Twenty-one (6.9%) of these cultures were positive for fungal organisms. The sensitivity and specificity of the KOH-CFW test were 29% and 93%, respectively. Clinicians' initial clinical impression based solely on patients' history and examination, without the aid of any histopathologic or biochemical test results, demonstrated a sensitivity and specificity of 33% and 89%, respectively.

CONCLUSIONS

The observed sensitivity and specificity of the KOH-CFW preparation are significantly lower than many previously reported values. In regions with low incidence of fungal keratitis, the KOH-CFW preparation may have diagnostic performance similar to that of the clinical impression formed only on the basis of history and physical examination.

Neutralizing antibodies for the prevention and treatment of COVID-19

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) initiates the infection process by binding to the viral cellular receptor angiotensin-converting enzyme 2 through the receptor-binding domain (RBD) in the S1 subunit of the viral spike (S) protein. This event is followed by virus-cell membrane fusion mediated by the S2 subunit, which allows virus entry into the host cell. Therefore, the SARS-CoV-2 S protein is a key therapeutic target, and prevention and treatment of coronavirus disease 2019 (COVID-19) have focused on the development of neutralizing monoclonal antibodies (nAbs) that target this protein. In this review, we summarize the nAbs targeting SARS-CoV-2 proteins that have been developed to date, with a focus on the N-terminal domain and RBD of the S protein. We also describe the roles that binding affinity, neutralizing activity, and protection provided by these nAbs play in the prevention and treatment of COVID-19 and discuss the potential to improve nAb efficiency against multiple SARS-CoV-2 variants. This review provides important information for the development of effective nAbs with broad-spectrum activity against current and future SARS-CoV-2 strains.

Inhibiting miR-129-5p alleviates inflammation and modulates autophagy by targeting ATG14 in fungal keratitis

To investigate the role of miR-129-5p in inflammation and autophagy in fungal keratitis, we established a keratitis mouse model infected with Fusarium solani (F. solani) and conducted experiments on corneal stromal cells infected with F. solani. The expression of miR-129-5p was detected via quantitative real-time polymerase chain reaction (PCR). The miR-129-5p antagomir was used to transfect cells and mice to study the regulatory role of miR-129-5p in autophagy and inflammation after fungal infection. The expression of Beclin1 and LC3B and colocalization of LC3B with lysosomes were detected via Western blotting and immunofluorescence. CCK-8 was used to determine the viability of corneal stromal cells. The expression of IL-1β were detected by ELISA. Bioinformatics software was used to predict the potential targets of miR-129-5p, which were verified by a luciferase reporter gene assay. RT-PCR showed that miR-129-5p expression in mouse corneas was significantly increased after infection with F. solani. Subconjunctival injection of the miR-129-5p antagomir significantly enhanced the proteins Beclin-1 and LC3B. At the same time, inhibiting miR-129-5p expression could reduce the inflammatory response in FK and significantly increase the viability of corneal stromal cells infected with F. solan. Moreover, the dual luciferase reporter assay indicated that Atg14 was a direct target of miR-129-5p. Our study shows that miR-129-5p is a novel small molecule that regulates autophagy by targeting Atg14, indicating that it may be a proinflammatory and therapeutic target for fungal keratitis.

Bilateral Trichosporon asahii keratitis after ptosis correction: A case report

RATIONALE

Fungal keratitis (FK) is a severe vision-threatening disease that can lead to corneal perforation or endophthalmitis despite proper treatment. It is important to diagnose the disease promptly due to its indolent nature and disproportionate disease symptoms. Trichosporon asahii is reported rarely as the causative organism of FK. We report a case of highly unusual bilateral T asahii keratitis following ptosis surgery.

PATIENT CONCERNS

An 86-year-old female underwent bilateral levator resection surgery for ptosis. Postoperatively, the patient complained of gradually worsening bilateral ocular pain and a decrease in visual acuity associated with a chronic non-healing epithelial defect.

DIAGNOSES

Both eyes of the patient were evaluated using best-corrected visual acuity, intraocular pressure, slit-lamp examination, fundus examination, and corneal culture. Multifocal deep stromal infiltrates were found in both corneas. Cultures from both corneal ulcers revealed growth of T asahii. Optical coherence tomographic examination showed bilateral macular edema.

INTERVENTIONS

The patient was treated with revisional ptosis surgery, an antifungal agent for the corneal ulcer, and intravitreal injection of steroid for macular edema.

OUTCOMES

Both eyes recovered well. Her best-corrected visual acuity improved from 20/200 to 20/40 in the right eye and from 20/100 to 20/40 in the left eye.

LESSONS

FK can develop in the cornea when certain risk factors are present, including recent lid surgery, chronic keratitis, and steroid eye drop use. Identification and correction of risk factors can be beneficial in the treatment of FK.

A novel 3D culture model of fungal keratitis to explore host-pathogen interactions within the stromal environment

Fungal keratitis (FK) pathology is driven by both fungal growth and inflammation within the corneal stroma. Standard in vitro infection models ̶ involving co-culture of the pathogen and the corneal cells in tissue culture medium ̶ are sufficient to probe host responses to the fungus; however, they lack the physiological structure and nutrient composition of the stroma to accurately study fungal invasiveness and metabolic processes. We therefore sought to develop a culture model of FK that would allow for both host and fungal cell biology to be evaluated in parallel. Towards this end, we employed a previously described system in which primary human cornea fibroblasts (HCFs) are cultured on transwell membranes, whereupon they secrete a three-dimensional (3D) collagen matrix that resembles the human stroma. We demonstrated that two common mold agents of FK, Fusarium petroliphilum and Aspergillus fumigatus, penetrated into these constructs and caused a disruption of the collagen matrix that is characteristic of infection. HCF morphology appeared altered in the presence of fungus and electron microscopy revealed a clear internalization of fungal spores into these cells. Consistent with this apparent phagocyte-like activity of the HCFs, mRNA and protein levels for several pro-inflammatory cytokines/chemokines (including TNFα, IL-1β, IL-6, and IL-8) were significantly upregulated compared to uninfected samples. We similarly found an upregulation of several HCF metalloproteases (MMPs), which are enzymes that breakdown collagen during wound healing and may further activate pro-inflammatory signaling molecules. Finally, several fungal collagenase genes were upregulated during growth in the constructs relative to growth in tissue culture media alone, suggesting a fungal metabolic shift towards protein catabolism. Taken together, our results indicate that this 3D-stromal model provides a physiologically relevant system to study host and fungal cell pathobiology during FK.

First report of human infection caused by Colletotrichum chlorophyti occurring in a post-corneal transplant patient with endophthalmitis

Keratomycosis or mycotic keratitis is recognized as one of the major causes of ophthalmic morbidity worldwide. The most common organisms linked to keratomycosis include Candida spp., Fusarium spp., and Aspergillus spp. However, varieties of saprobic fungi have been reported as causative agents of keratomycosis. Amongst these are members of the genus Colletotrichum. Herein we present the first reported case of C. chlorophyti infection in a post-corneal transplant patient, suggesting an increasing role for Colletotrichum species as emerging human pathogens, particularly in the transplant population.

Evaluation of Polymerase Chain Reaction over Routine Microbial Diagnosis for the Diagnosis of Fungal Keratitis

SIGNIFICANCE

The significance of the study is that, although conventional culture remains the criterion standard for identifying the causative fungal pathogens, polymerase chain reaction (PCR) may serve as a powerful and high-throughput tool for the early and definitive diagnosis of high-risk patients with mycotic keratitis owing to high sensitivity and specificity.

PURPOSE

This study was focused on comparing the results of PCR with traditional microbial studies for the detection and identification of fungal pathogens in patients with clinically suspected fungal keratitis.

METHODS

Corneal scrapings were collected from 59 patients with clinically suspected fungal keratitis for routine culture, staining, and seminested PCR assay for fungal pathogen identification. The results of PCR were compared with a conventional microbial workup (smear and culture). The samples that were unidentified by culture but were amplified by PCR were further identified by nucleotide sequencing.

RESULTS

Of the 59 patients with suspected fungal keratitis, 38 (64.40%) were found to be positive by PCR assay, 24 (40.67%) by culture, 18 (20.3%) by potassium hydroxide wet mount, and 8 (13.5%) by Gram stains for fungal pathogens. All the 24 isolates found positive with culture were also positive with PCR, so they had not been sequenced for molecular identification. The remaining 14 isolates that were positive with PCR but negative with culture were further identified as Cladosporium cladosporioides, Simplicillium species, Fusarium solani, Alternaria tenuissima, Chaetomium globosum, Penicillium citrinum, and Rhizopus microsporus by sequencing up to the species level.

CONCLUSIONS

The PCR was able to detect the presence of fungal pathogens in a high proportion of culture-negative cases. This study suggests that PCR may serve as a rapid, important complement to traditional culture with high-throughput means of fungal pathogen identification in patients with clinically suspected fungal keratitis.

Transcriptome Analysis of the Gene Expression Profiles Associated with Fungal Keratitis in Mice Based on RNA-Seq

Purpose

Fungal keratitis (FK) is an eye disease that can lead to blindness and has a high incidence worldwide. At present, there is no effective treatment for this disease. There are innate immune response mechanisms that protect against fungal infections. One example is C-type lectin receptors (CLRs), which can identify fungal invaders and trigger signal transduction pathways and cellular responses to eliminate pathogens. However, previous studies have focused mostly on single-receptor factors, and a systematic analysis of the genetic factors underlying the pathogenesis of FK has not been conducted. This study aimed to investigate the molecular mechanisms of FK in terms of genomics and to further elucidate its pathogenesis.

Methods

We performed a transcriptome analysis of a mouse model of FK using RNA sequencing to obtain the relevant gene expression profiles and to identify differentially expressed genes, signaling pathways, and regulatory networks of the key genetic factors in the pathogenesis of murine FK.

Results

Several genes that are significantly associated with FK and serve as markers of FK, such as the inflammatory cytokine genes IL1B, IL6, IL10, IL23, and TNF, were identified. The mRNA and protein expression patterns of IL-1β, IL-6, and TNF-α in the corneas of mice with FK were validated by quantitative RT-PCR and Luminex multiplex assay technology. The Wnt, cGMP–PKG, and Hippo signaling pathways were significantly enriched during fungal infection of mouse corneas.

Conclusions

Our study may help to elucidate the mechanisms of FK pathogenesis and to identify additional candidate drug targets for the treatment of FK.

The role of fungi in fungal keratitis

Fungal keratitis (FK) accounts for approximately half of the microbial keratitis encountered in low middle income countries (LMICs) and predominantly affect the working rural-poor. FK causes significant morbidity with the majority of patients left with moderate or worse visual impairment and approximately 25% requiring expensive and often unsuccessful surgical interventions. The severity of FK and the resultant corneal damage or resolution can be attributed to i) the virulence and bioburden of the fungal pathogen, ii) the host defense mechanism and immune response and iii) sub-optimal diagnostics and anti-fungal treatment strategies. This review provides a comprehensive overview of the multifaceted components that drive FK progression and resolution, highlighting where knowledge gaps exist and areas that warrant further research.

In-vitro assessment of first-line antifungal drugs against Aspergillus spp. caused human keratomycoses

BACKGROUND AND OBJECTIVES

Aspergillus keratitis are in the increasing trend and reported as the second most common cause of mycotic keratitis in developing countries. The present study was designed to isolate, identify Aspergillus spp. from the keratits/corneal ulcer patients attending a tertiary care eye hospital, Coimbatore, South India and to assess the minimum inhibitory concentrations (MICs) against ten clinically used first-line antifungal drugs.

METHODS

A total of seventy-three Aspergillus strains isolated from corneal scrapings were included and assessed for a period of one year. All isolates were identified up to the species level by morphological observations. Antifungal drug susceptibilities were determined against a standard panel of antifungal agents.

CONCLUSIONS

Five different species of aspergilli, A. flavus (n=53), A. fumigatus (n=14), A. terreus (n=9), A. tamarii (n=6) and A. niger (n=3) were identified based on morphological features. Minimum inhibitory concentration analyses indicated that, voriconazole, natamycin, itraconazole, clotrimazole, econazole followed by ketoconazole shall be the order of choices for the effective treatment for Aspergillus keratitis.

[Epidemiology and treatment of fungal keratitis]

Infectious keratitis in most cases is caused by bacterial, viral or fungal agents, but their structure is changing. Some researchers have noted a substantial increase in fungal corneal lesions in recent decades, but important local etiological therapy remains unavailable in developing countries. While bacterial keratitis and ophthalmoherpes are controlled by widely available local etiotropic therapy, treatment of keratomycosis in the Russian Federation is carried out with off-label medicine. Lack of skills and availability of diagnostic methods and official etiotropic therapy creates unequal conditions for ophthalmology specialists in the fight against ophthalmomycosis. In part, this causes a reduced level of «myco-caution», which leads to long-term ineffective treatment using antibacterial drops, lasting suffering of patients, and results in the loss of the eye functionally and - in some cases - anatomically. Therefore, the study of fungal keratitis remains relevant. The article provides an overview of research data on current epidemiology in different regions of the world, analyzes available antifungal drugs and the prospects for development of affordable and effective treatment of fungal keratitis.

Experimental Models for Fungal Keratitis: An Overview of Principles and Protocols

Fungal keratitis is a potentially blinding infection of the cornea that afflicts diverse patient populations worldwide. The development of better treatment options requires a more thorough understanding of both microbial and host determinants of pathology, and a spectrum of experimental models have been developed toward this end. In vivo (animal) models most accurately capture complex pathological outcomes, but protocols may be challenging to implement and vary widely across research groups. In vitro models allow for the molecular dissection of specific host cell–fungal interactions, but they do so without the appropriate environmental/structural context; ex vivo (corneal explant) models provide the benefits of intact corneal tissue, but they do not provide certain pathological features, such as inflammation. In this review, we endeavor to outline the key features of these experimental models as well as describe key technical variations that could impact study design and outcomes.

Bibliometric and visualized analysis of global research on fungal keratitis from 1959 to 2019

BACKGROUND

Fungal keratitis is one of the leading causes of ocular morbidity. The prognosis of fungal keratitis is poorer than many other forms of keratitis but the research of which relatively lags behind. We conducted a bibliometric and visualized analysis in order to characterize the overall status, general trends and current foci of keratomycosis research field.

METHODS

Literature database ranged from 1959 to 2019 was obtained from web of science core collection and analyzed by Citespace and VOSviewer software.

RESULTS

A total of 1906 papers of fungal keratitis were retrieved and derived a 27,917 references document set. The number of publications increased rapidly in past 30 years. Cornea was the journal published most papers of keratomycosis. The leading countries were United States of America (USA), India and Peoples Republic of China (PRC), from where came the most productive and most cited institutions and authors. Co-cited reference analysis revealed the most cited manuscripts were concerned about epidemiology or spectrum. Lens-associated Fusarium, amphotericin B, voriconazole, corneal cross-linking, predisposing factor are some of the high frequency topics in clustered co-cited reference analysis and co-occurrence keywords analysis. Burst detection analysis of keywords showed ocular drug delivery was the new research foci.

CONCLUSION

From this study, we received an overall view to the current status, trends and hot spots of fungal keratitis research field. Visualized bibliometric analysis is an efficient way for literature learning and useful for future researchers.

Etiology and Risk Factors for Infectious Keratitis in South Texas

Purpose

To determine the causative organisms and associated risk factors for infectious keratitis in South Texas.

Methods

This retrospective study was performed at a tertiary teaching hospital system in South Texas. Medical records of all patients who presented with infectious keratitis from 2012 to 2018 were reviewed. Only patients with culture-proven bacterial, fungal, and Acanthamoeba keratitis were included.

Results

In total, 182 eyes of 181 patients had culture-proven bacterial, fungal, or Acanthamoeba keratitis. The age of patients ranged from 3 to 93 years, with a mean of 48.3 ± 20.8 years. The most common etiologic agent was bacteria, with 173 bacterial cultures (95.1%) recovered, followed by 13 fungal cultures (7.1%), and 3 Acanthamoeba cultures (1.6%). Of the 218 bacterial isolates, coagulase-negative Staphylococcus was the most common (25.7%), followed by Pseudomonas aeruginosa (23.4%), Staphylococcus aureus (11.0%), and Moraxella (7.8%). Fusarium was the most common fungal isolate (46.2%). The most common risk factors for infectious keratitis included contact lens wear (32.4%), underlying corneal disease (17.6%), trauma (14.3%), and ocular surface disease (13.7%).

Conclusions

Bacteria are the most common cause of infectious keratitis in this patient population, with coagulase-negative Staphylococcus and Pseudomonas as the most common isolates. The prevalence of culture-positive fungal keratitis is significantly lower than that of bacterial keratitis. Contact lens wear is the most common risk factor associated with infectious keratitis in South Texas.

Diagnostic and Management Strategies of Aspergillus Endophthalmitis: Current Insights

Fungal endophthalmitis is subsequent to endogenous or exogenous infection and represents an important complication of ocular surgery which may lead to significant visual loss and blindness. The prognosis is poor because of delayed diagnosis and limited availability of effective antifungal drugs with good ocular penetration. Furthermore, the critical issue in diagnosing fungal infection of the eye is microbiological identification of the etiologic agent in clinical samples. Aspergillus is among the most frequent isolated organisms in fungal endophthalmitis. Early diagnosis is essential to prevent severe complications and blindness. Treatments include local, systemic and surgical therapeutic strategies. The purpose of the present review is the analysis of the current procedures adopted to promptly diagnose and treat Aspergillus endophthalmitis.

Risk Factors of Microbial Keratitis in Uganda: A Case Control Study

Purpose: Microbial keratitis (MK), is a frequent cause of sight loss worldwide, particularly in low and middle-income countries. This study aimed to investigate the risk factors of MK in Uganda.Methods: Using a nested case control, we recruited healthy community controls for patients presenting with MK at the two main eye units in Southern Uganda between December 2016 and March 2018. Controls were individually matched for age, gender and village of the cases on a 1:1 ratio. We collected information on demographics, occupation, HIV and Diabetes Mellitus status. In STATA version 14.1, multivariable conditional logistic regression was used to generate odds ratios for risk factors of MK and a likelihood ratio test used to assess statistical significance of associations.Results: Two hundred and fifteen case-control pairs were enrolled. The HIV positive patients among the cases was 9% versus 1% among the controls, p = .0003. Diabetes 7% among the cases versus 1.4% among the controls, p = .012. Eye trauma was 29% versus 0% among the cases and controls. In the multivariable model adjusted for age, sex and village, HIV (OR 83.5, 95%CI 2.01-3456, p = .020), Diabetes (OR 9.38, 95% CI 1.48-59.3, p = .017) and a farming occupation (OR 2.60, 95%CI 1.21-5.57, p = .014) were associated with MK. Compared to a low socio-economic status, a middle status was less likely to be associated with MK (OR 0.29, 95%CI 0.09-0.89, p < .0001).Conclusion: MK was associated with HIV, Diabetes, being poor and farming as the main occupation. More studies are needed to explore how these factors predispose to MK.

CRISPR/Cas9-Mediated Gene Replacement in the Fungal Keratitis Pathogen Fusarium solani var. petroliphilum

Fungal keratitis (FK) is a site-threatening infection of the cornea associated with ocular trauma and contact lens wear. Members of the Fusarium solani species complex (FSSC) are predominant agents of FK worldwide, but genes that support their corneal virulence are poorly understood. As a means to bolster genetic analysis in FSSC pathogens, we sought to employ a CRISPR/Cas9 system in an FK isolate identified as Fusarium petroliphilum. Briefly, this approach involves the introduction of two components into fungal protoplasts: (1) A purified Cas9 protein complexed with guide RNAs that will direct the ribonuclease to cut on either side of the gene of interest, and (2) a “repair template” comprised of a hygromycin resistance cassette flanked by 40 bp of homology outside of the Cas9 cuts. In this way, Cas9-induced double strand breaks should potentiate double homologous replacement of the repair template at the desired locus. We targeted a putative ura3 ortholog since its deletion would result in an easily discernable uracil auxotrophy. Indeed, 10% of hygromycin-resistant transformants displayed the auxotrophic phenotype, all of which harbored the expected ura3 gene deletion. By contrast, none of the transformants from the repair template control (i.e., no Cas9) displayed the auxotrophic phenotype, indicating that Cas9 cutting was indeed required to promote homologous integration. Taken together, these data demonstrate that the in vitro Cas9 system is an easy and efficient approach for reverse genetics in FSSC organisms, including clinical isolates, which should enhance virulence research in these important but understudied ocular pathogens.

Severe mycotic keratoconjunctivitis caused by Fusarium sp. in an immunocompetent child successfully treated with intravenous voriconazole and keratoplasty: case report and short review of the literature

Background

Pediatric mycotic infections in the eye are uncommon. However, ophthalmic infections by several fungal species have been described in immunocompetent subjects. Mycotic keratitis with or without conjunctivitis (MK) may account for more than 50% of all cases, particularly in tropical and sub-tropical areas. The leading mechanism is trauma. Treatment of MK is managed by medical (antifungal agents) and/or surgical means. This is the first case report of a patient with MK by Fusarium spp. successfully treated with keratoplasty and intravenous voriconazole, along with topical natamycin.

Methods

Keratoplasty was performed and cultures obtained. Both Blood and Sabouraud Agars were used for cultures, and Lactophenol Cotton Blue Staining for microscopic observation.

Results

A healthy, 10 year-old female, from the sub-tropical area of Sinaloa, Mexico, was admitted at both the CODET Vision Institute and the General Hospital of Tijuana, Mexico. Seven days after a direct trauma of the right cornea, the patient complained of progressive blurred vision, burning sensation, and itchiness. Clinical examination showed severe keratoconjunctivitis, and a necrotic slough on the cornea. Fungal colonies grew, and microscopic visualization showed typical ovoid, sickle-cell shaped macroconidia characteristics of Fusarium spp. The patient received intravenous voriconazole (200 mg every 12 h) and topical natamycin for 7 days prior and 6 days after keratoplasty. Topical natamycin was continued for 3 weeks. At 1-month follow-up, the patient's outcome was significantly improved, with 90% vision recovery.

Conclusion

This is the first pediatric case report of severe MK by Fusarium spp. successfully treated with combined intravenous voriconazole, keratoplasty and topical natamycin.

Comparison of the Ocular Penetration and Pharmacokinetics Between Natamycin and Voriconazole After Topical Instillation in Rabbits

PURPOSE

To investigate the ocular penetration of natamycin (NAT) and voriconazole (VRC) after topical instillation in New Zealand white rabbits using simplified liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography.

METHODS

Seventy-eight healthy rabbits were randomly divided into 3 groups. In the first 2 groups, 72 rabbits were used for single-dose testing (36 for NAT, 36 for VRC), in which 50 μL of 5.0% NAT or 1.0% VRC was instilled into the rabbits' left eyes. In the 3rd group, 6 rabbits were used for repeated-dose testing in which 50 μL of 5.0% NAT was instilled into their left eyes 12 times (once per hour) during the daytime. These animals were sacrificed immediately to collect their aqueous humors and corneas.

RESULTS

After a single topical instillation, the highest concentrations in the cornea and aqueous humor for VRC were 34.1 μg/g and 14.7 μg/mL, respectively. The permeability ratios of aqueous/cornea were from 0.1 to 1.26. The highest concentrations in cornea and aqueous humor for NAT were 299.3 ng/g and 27.1 ng/mL, respectively. The permeability ratios of aqueous/cornea were from 0.02 to 0.23. In the repeated-dose group, the NAT concentrations in the cornea and aqueous humor were 10,569 ng/g and 54.4 ng/mL, respectively. The permeability ratio was as low as 0.0051.

CONCLUSION

The better corneal penetration of VRC suggests that it is more suitable for deep corneal fungal infections than NAT via topical ocular administration.

Inflammation and oxidative stress in corneal tissue in experimental keratitis due to Fusarium solani: Amelioration following topical therapy with voriconazole and epigallocatechin gallate

Combined antifungal and antioxidant therapy may help to reduce oxidative stress in fungal keratitis. Experimental Fusarium solani keratitis was induced by application of F. solani conidia to scarified cornea (right eye) of 16 rabbits (another four rabbits were negative controls [Group I]). Five days later, F. solani-infected animals began receiving hourly topical saline alone (Group II), voriconazole (10 mg/mL) alone (Group III), epigallocatechin gallate (EGCG, 10 mg/mL) alone (Group IV) or voriconazole and EGCG (Group V). Twenty days post-inoculation, corneal lesions were graded. After animal sacrifice, excised corneas underwent histopathological and microbiological investigations. Corneal tissue levels/activities of interleukin 1 beta (IL-1β) and tumour necrosis factor alpha (TNF-α) gene mRNA transcripts, matrix metalloproteinase (MMP) 2 and 9 proteins, malondialdehyde (MDA) and reduced glutathione (GSH), and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), were also measured. Clinical and histopathological scores (severity of corneal lesions; [P < .05]) and mean levels (P < .05) of IL-1β and TNF-α mRNA transcripts, MMP 2, MMP 9 and MDA were Group II > Groups IV and III > Groups V and I. Mean SOD, CAT, GPx and GSH levels (P < .05) were Group II < Groups IV and III < Groups V and I. Topical voriconazole with EGCG apparently reduces inflammation in experimental F. solani keratitis, as manifested by improved clinical, histological, microbiological and molecular parameters.

Keratitis secondary to Fusarium spp. in Spain 2012-2014

OBJECTIVE

To describe the clinical-epidemiological characteristics of a case series of fungal keratitis associated with Fusarium spp.., in Spain during the years 2012 to 2014.

METHODS

A retrospective study of a case series was conducted on a systematic random sample of 10% of patients identified in Health Centres of provincial capitals (n=250). The centres were asked whether they had been presented with cases of Fusarium spp. keratitis characterised by microbiological methods. Of the 23 centres that responded, 14 had detected cases, with 13 of them accepting to participate, and 11 of them completing the study. The latter being sent a previously validated questionnaire. The variables analysed were: age, gender, habitual residence, profession, disease and medical history (previous systemic and ocular diseases, previous eye surgeries), and their outcomes.

RESULTS

The response rate was 92%, identifying 23 cases of Fusarium spp.. of which 21 (91.3%) of them lived in urban areas. The professions most affected by the disease included chefs, administrative, and technical, with 13 cases (56.5%). The treatment guidelines established to confirm the infection showed the combined use of topical antibiotics associated with antiviral and/or antifungal agents. The use of contact lenses (86.9%) was the main risk factor.

DISCUSSION

This study showed that this is a rare disease in Spain, but that a large percentage of people who present with the disease are resident in urban areas, and they work in closed environments, focusing attention on microtraumas caused by use of contact lenses.

Scedosporium Keratitis: An Experience From a Tertiary Eye Hospital in South India

PURPOSE

To determine the clinical profile and prognosis of Scedosporium keratitis.

METHODS

All culture-proven cases were retrospectively analyzed for demographics, clinical characteristics, treatment offered, and resolution time with sequel.

RESULTS

Among the 1792 culture-proven fungal keratitis cases in the study period, 10 (0.6%) were the result of Scedosporium. The mean age of patients was 44.2 years. Eight patients were male. A history of trauma was present in 8 patients. The infiltrate involved the center of the cornea in 5 patients, whereas 4 patients had paracentral involvement and 1 patient had limbal involvement. The mean maximum diameter of infiltrate was 3.4 mm. Five cases were prescribed topical natamycin alone: 4 patients were successfully treated with this monotherapy, whereas 1 patient was lost to follow-up, but the records of the last visit revealed healing. Three patients were treated with a combination therapy of topical natamycin and 1% voriconazole: 2 patients showed complete healing of the ulcer, and 1 patient progressed to corneal perforation necessitating penetrating keratoplasty.

CONCLUSIONS

To our knowledge, this is the largest case series on Scedosporium keratitis to date. This is the first study to report successful treatment of this infection with topical natamycin monotherapy. The outcome may improve if appropriate medical therapy is started early.

Fungal keratitis in the Republic of Ireland

PurposeFungal keratitis is relatively rare in temperate climates with only one previous population-based study, which reported a minimum annual incidence of 0.32 per million population in the United Kingdom. We performed a nationwide study in the Republic of Ireland of cases over a 6-year period to establish the incidence, risk factors, treatment, and outcomes of fungal keratitis.Patients and methodsAll corneal scraping specimens positive for fungal species over a 6-year period were identified at the microbiology departments of the seven main ophthalmology units in the Republic of Ireland. Census data was used to establish national minimum annual incidence.ResultsForty-two eyes were treated for confirmed fungal keratitis during the 6-year period. This resulted in a minimum incidence of 1.53 cases per million population per year. Twenty-eight of 42 cases (67%) were due to filamentary fungi, with the most common species being Aspergillus. Pre-existing ocular surface disease was the most common risk factor constituting 42.9%; 26.2% underwent keratoplasty. No eyes underwent evisceration. Two eyes resulted in a level of vision of no perception of light. The mean LogMAR acuity in the remainder of cases was 0.89 with a range from -0.10 to 4.00.ConclusionThis study demonstrates a much higher minimum annual incidence than previously reported. The causative organism is highly related to risk factor. The range of visual outcomes remains broad in all subgroups. The wide range of outcomes and treatments used highlights the need for better evidence-based guidelines for fungal keratitis.